Following the work of Grad-CAM [1]}, we also conduct human evaluation on the widely used platform (AMT: Amazon Mechanical Turk) to further evaluate the quality of overall activation maps generated by different methods.
Based on Table REF , two comparison pairs are formed as “Decomposition" vs. “Grad-CAM" and “Decomposition" vs. “Grad-CAM (no norm)". For each comparison pair, the AMT raters are asked to carefully check the visual explanation generated from two different methods as shown in Fig. REF . Each visual explanation contains an image pair with birds from the same species and the top activated regions (\(2\%\)  pixels) are highlighted based on the overall activation map of one competing method. We denote these two methods as robot A and robot B in the questionnaire. The raters will decide which robot they think is more reasonable in a five-point Likert scale as shown in Fig. REF .
